Synthesis Of New Class Research Articles

Solvent-free and montmorillonite K10-catalyzed domino reactions for the synthesis of pyrazoles with alkynylester as a dual synthon

A highly regioselective, solvent-free and montmorillonite K10 clay-catalyzed domino process with an unprecedented C–C bond formation reaction is described for the synthesis of new class of tri-substituted and di-substituted pyrazole derivatives.

Removal of cationic methylene blue dye using magnetic and anionic-cationic modified montmorillonite: kinetic, isotherm and thermodynamic studies

In this study, the synthesis of new class of the modified montmorillonite with magnetic nanoparticles and surfactants was studied. The synthesis was carried out via intercalation of a mixture of sodium eicosenoate (SEIA, anionic surfactant) and cetyltrimethylammonium chloride (CTMAC, cationic surfactant) on the surface or within interlamellar spaces of montmorillonite (Mt) and thereafter the immobilization of Fe3O4 MNPs (magnetic nanoparticles) to afford Fe3O4-CTMAC/SEIA-Mt system. Next, the nanocomposite of CTMAC-Mt, SEIA-Mt, CTMAC/SEIA-Mt and CTMAC/SEIA-Fe3O4-Mt (In this case, magnetic montmorillonite was primarily prepared and then modified with a mixture of CTMAC/SEIA surfactants) were also synthesized. The prepared nanocomposite systems were characterized using FT-IR, XRD, SEM, EDX, TGA and VSM analyses and then utilized for the removal of cationic methylene blue (MB) dye from aqueous solutions. Among the examined composite systems, Fe3O4-CTMAC/SEIA-Mt showed a superior adsorption capacity. In this area, the influence of adsorbent dosage, contact time, initial concentration of MB and temperature towards the adsorption of MB on Fe3O4-CTMAC/SEIA-Mt system was also investigated. The obtained results exhibited that the kinetic of adsorption and the model of isotherm obeyed from the pseudo-second order and Langmuir model, respectively. Moreover, Fe3O4-CTMAC/SEIA-Mt system showed an extraordinary adsorption capacity for MB (246 mg g–1). Because of superparamagnetic characteristic of magnetite, the adsorbent of Fe3O4-CTMAC/SEIA-Mt can be easily separated from the reaction mixture by an external magnetic field. Thermodynamic studies also represented that the adsorption of MB on Fe3O4-CTMAC/SEIA-Mt was endothermic and it was carried out as a spontaneous process.

High‐Performance and Stable Perovskite Solar Cells Based on Dopant‐Free Arylamine‐Substituted Copper(II) Phthalocyanine Hole‐Transporting Materials

AbstractA power conversion efficiency (PCE) as high as 19.7% is achieved using a novel, low‐cost, dopant‐free hole transport material (HTM) in mixed‐ion solution‐processed perovskite solar cells (PSCs). Following a rational molecular design strategy, arylamine‐substituted copper(II) phthalocyanine (CuPc) derivatives are selected as HTMs, reaching the highest PCE ever reported for PSCs employing dopant‐free HTMs. The intrinsic thermal and chemical properties of dopant‐free CuPcs result in PSCs with a long‐term stability outperforming that of the benchmark doped 2,2′,7,7′‐Tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐Spirobifluorene (Spiro‐OMeTAD)‐based devices. The combination of molecular modeling, synthesis, and full experimental characterization sheds light on the nanostructure and molecular aggregation of arylamine‐substituted CuPc compounds, providing a link between molecular structure and device properties. These results reveal the potential of engineering CuPc derivatives as dopant‐free HTMs to fabricate cost‐effective and highly efficient PSCs with long‐term stability, and pave the way to their commercial‐scale manufacturing. More generally, this case demonstrates how an integrated approach based on rational design and computational modeling can guide and anticipate the synthesis of new classes of materials to achieve specific functions in complex device structures.

Highly selective palladium-catalyzed one-pot, five-fold B-H/C-H cross coupling of monocarboranes with alkenes.

Palladium-catalyzed dehydrogenative B-H/C-H cross coupling of monocarborane anions with alkenes is reported, allowing for the first time the isolation of selectively penta-alkenylated boron clusters. The reaction cascade is regioselective for the cage positions, leading directly to B2-6 functionalization. Under mild and convenient conditions, styrenes, benzylic alkenes and aliphatic alkenes are demonstrated to be viable coupling partners with exclusive vinyl-type B-C bond formation. Multiple subsequent transformations provide access to directing group-free products, chiral derivatives and penta-alkylated cages. The five-fold coupling, combined with the latter reactions, represents a powerful methodology for the straightforward synthesis of new classes of boron clusters.

The first target specific, highly diastereoselective synthesis, design and characterization of pyranoquinolinyl acrylic acid diastereomers as potential α-glucosidase inhibitors

In the present investigation we report the first target specific, highly diastereoselective synthesis of new class of pyranoquinolinyl/furoquinolinyl-acrylic acid diastereomers and evaluation of their invitro α-glucosidase inhibitory activity. All the products were thoroughly characterized by 1H NMR, 13C NMR, FT-IR, Mass spectral and CHN analysis. A highly diastereoselective target specific route of synthesis for the biologically active diastereomers were developed by usingchiral catalyst Europium tris[3-heptafluoropropylhydroxyl methylene]-(−)-camphorate (A) or Europiumtris[3-(trifluoromethyl)hydroxylmethylene]-(+)-camphorate (B). It was found that among a set of 4 diastereomeric products obtained, exodiasteromers of pyranoquinolinyl acrylic acid adducts exhibited relatively high α-glucosidase inhibitory activity. The newly synthesized compounds exhibited IC50 values in the range of (0.40 ± 0.02–30.3 ± 0.84 μM) as compared to standard acarbose (IC50 = 0.65 ± 0.02 μM). It was found that compounds 11a, 11c, 11d and 12d were found to be more active than standard acarbose. It was also found that unsubstituted compound (11a) or compounds with chlorine or methoxy substituent (11c, 11d, 12d) showed potential α-glucosidase inhibitory activity. However a reversal in activity was observed with Nitro substituent (11b, 13b) wherein the endodiastereomers were found to be more active than exodiastereomers. Molecular docking studies were used for design of the compound and understand the mode of binding between the compound and target enzyme. A plausible mechanism for the diastereoselective synthesis was also proposed.

Design and synthesis of novel 6-substituted quinazoline-2-thiols.

A novel design and efficient protocol for the synthesis of new class of 6-substituted quinazoline-2-thiols is reported. The derivatization of the thioquinazolines is achieved in a strategic manner using 2-aminobenzylamine. The functionalization of the aniline followed by construction of the heterocyclic ring provides a facile way to synthesize these bifunctional quinazolines.

Bromo-substituted cibalackrot backbone, a versatile donor or acceptor main core for organic optoelectronic devices

Cibalackrot (Ci-I), one of the latest highly conjugated compound possessing bis-lactam structure, was investigated with respect to their brominated derivatives in order to determine their suitable substitution points for the syntheses of new class of small molecules for optoelectronic devices. 7,14-Bis(4-bromophenyl) (Ci-II) and 3,10-dibromo (Ci-III) derivatives of cibalackrot possess moderately narrow band gaps of 2.15 and 2.09 eV, respectively. Notably, Ci-III dye exhibits more red-shifted ultraviolet–visible (UV–vis) absorption and fluorescence emission spectra as compared to that of Ci-II dye because Ci-III shows more prominent intramolecular charge transfer (ICT) complex than that of Ci-II dye. Electron mobilities of the order of 7.0 × 10−4 cm2/V and 3.1 × 10−4 cm2/V were measured using Ci-II and Ci-III as active layer, respectively. Charge transfer properties of the molecules were investigated in bulk heterojunction device configuration wherein Ci-III showed p-type behavior against n-type PCBM in photovoltaic device. Photovoltaic performance of Ci-III dye which was used as donor component is 20 times higher than that of the device in which this dye was used as acceptor.

Simple synthesis of 5-amino-8-nitro-7-aryl-3,7-dihydro-2H-thiazolo[3,2-a]pyridine-6-carboxamide derivatives

ABSTRACTAn easy, efficient, and environmentally benign synthesis of new class of thiazolopyridine carboxamide derivatives is reported via one-pot, multi-component reaction of 2-(nitromethylene)thiazolidine derived from the addition of cysteamine hydrochloride to nitro ketene dithioacetal with aromatic aldehydes and cyanoacetamide using catalytic amount of triethylamine (Et3N) in ethanol/water at reflux in good to excellent yields.

Synthesis of New Class of Copper(II) Complex-Based FeNi3/KCC-1 for the N-Formylation of Amines Using Dihydrogen and Carbon Dioxide

This study investigated the potential application of an efficient, easily recoverable, and reusable copper(II)-based catalyst bearing polyvinyl alcohol (PVA) immobilized on FeNi3/KCC-1/APTPOSS [FeNi3/KCC-1/APTPOSS/TCT/PVA/Cu(II)] magnetic nano-particles (MNPs) for the N-formylation of amines via CO2 hydrogenation. FeNi3/KCC-1/TCT/PVA/Cu(II) MNPs were thoroughly characterized by transmission electron microscopy, field emission-scanning electron microscopy, vibrating sample magnetometry, thermo-gravimetric analysis, inductively coupled plasma-mass spectrometry (ICP-MS), and the Brunauer, Emmett, and Teller method. After the reaction, only minor changes to the morphology of the catalyst recycled by the ICP-MS were evidenced, thus corroborating its robustness.

Synthesis of Isoxazolidinyl Epoxides by Oxone Treatment of 2,3-Dihydroisoxazoles in Acetone–Water Solution: A New Stereoselective Approach to Hydroxy-Substituted Isoxazolidines

A practical and efficient synthesis of new class of isoxazoli­dinyl epoxides by direct treatment of 4,5-unsubstituted 2,3-dihydroisoxazoles with Oxone and NaHCO3 in acetone/water solution is described. All epoxidation reactions proceed with excellent anti-selectivity and provide stable products in very good yields. A concept for the development of stereoselective approach to 3,4-trans-hydroxy-substituted isoxazolidines, namely triazole derivatives as important molecules in medicinal chemistry is presented. The synthesis is characterized by highly syn-stereoselective conversion of epoxides to anomeric bromoisoxazolidines, which are found to be powerful reaction intermediates for the coupling reactions with various nucleophiles.

Evaluation of the optical properties of photoconductive Eosin/PMMA nanocomposite film for flexible optoelectronic applications

The maturity of flexible photoconductive polymeric composites through the incorporation of novel photoconductive pigments in the nanosclae into the polymer matrices have been recognized as promising nanocomposites for future organic optoelectronic. Here, we report the synthesis of new class of nanocomposites with promising optoelectronic features. These nanocomposites have been developed through the incorporation of Eosin as photoconductive filler into poly(methyl methacrylate). Thin films of these novel nanocomposites were made via spin coating technique. The topography and the distribution of the Eosin nanoparticles into the PMMA were appraised by the scanning electron microscopy (SEM) and the atomic force microscopy (AFM). Films with average thickness of 50nm and root mean square roughness of 1.7nm have been obtained. The optical behavior of these films has been studied based on various theoretical models. The optical behavior of the prepared nanocomposite films followed the single oscillator model. The spectral distribution of the index of refraction, extinction coefficient and permittivity was fitted by Wemple–DiDomenico model. The optical parameters such as lattice dielectric constant (ε∞), volume energy loss (VELF) and surface energy loss functions (SELF) were estimated. At all incident photon energies, the VELF values were larger than that of SELF, implying the opportunity of using these films as photoconductive optical lenses.

Synthesis and Antimicrobial Activity of New Pyrazoles and Chalcones Derived from Cyclic Imides

In the present work, an efficient synthesis of new class of Pyrazoles and Chalcones has been created through response of cyclic imides, p-chloro benzaldehyde/hydrazine hydrate in presence of catalyst neutral alumina. Pyrazoles and Chalcones as heterocyclic-moieties special thoughtful field and are readied by means of carbonheteroatom and carbon-carbon bond arrangement. The present technique contribute a novel and proficient strategy for the synthesis of Pyrazoles and Chalcones with a few points of interest, for example, excellent yields, short reaction time, better recoverability and low catalyst lading. The mixes were relinquished for antimicrobial exercises against bacterial strains gram positive microscopic organisms Staphylococcus aureus, Bacillus subtilis and gram negative microbes Escherichia coli, Pseudomonas aeruginosa along with two fungal strains Candida alb cans and Aspergillus niger. Some of the compounds showed representative inhibitory action against the bacterial and fungal strains.

Synthetic approach and functionalization of novel 4-anilinoquinolino-quinazoline heterocyclic scaffolds

An efficient and high yielding protocol is reported for the synthesis of new class of 4-anilinoquinolino-quinazoline hybrids. The target compounds were prepared first by the reaction of 2-aminobenzamide with 2-chloroquinoline-3-carbaldehydes. After oxidation and chlorination, the key 2-quinolyl-4-chloroquinazolines were converted to the corresponding 2-(2-arylaminoquinolyl)-4-arylaminoquinazolines and N-heteroaryl-2-(2-(heteroarylamino)quinolin-3-yl)quinazolin-4-amines.

Development of l-Tyrosine-Based Enzyme-Responsive Amphiphilic Poly(ester-urethane) Nanocarriers for Multiple Drug Delivery to Cancer Cells.

New classes of enzymatic-biodegradable amphiphilic poly(ester-urethane)s were designed and developed from l-tyrosine amino acid resources and their self-assembled nanoparticles were employed as multiple drug delivery vehicles in cancer therapy. The amine and carboxylic acid functional groups in l-tyrosine were converted into dual functional ester-urethane monomers and they were subjected to solvent free melt polycondensation with hydrophilic polyethylene glycols to produce comb-type poly(ester-urethane)s. The phenolic unit in the l-tyrosine was anchored with hydrophobic alkyl side chain to bring appropriate amphiphilicity in the polymer geometry to self-assemble them as stable nanoscaffolds in aqueous medium. The topology of the polymer was found to play a major role on the glass transition, crystallinity, and viscoelastic rheological properties of l-tyrosine poly(ester-urethane)s. The amphiphilic polymers were self-assembled as 200 ± 10 nm nanoparticles and they exhibited excellent encapsulation capabilities for anticancer drugs such as doxorubicin (DOX) and camptothecin (CPT). In vitro drug release studies revealed that the drug-loaded l-tyrosine nanoparticles were stable at extracellular conditions and they underwent enzymatic-biodegradation exclusively at the intracellular level to release the drugs. Cytotoxicity studies in the cervical cancer (HeLa) and normal WT-MEFs cell lines revealed that the nascent l-tyrosine nanoparticles were nontoxic, whereas the CPT and DOX drug-loaded polymer nanoparticles exhibited excellent cell killing in cancer cells. Confocal microscopic imaging confirmed the cellular internalization of drug-loaded nanoparticles. The drugs were taken up by the cells much higher quantity while delivering them from l-tyrosine nanoparticle platform compared to their free state. Flow cytometry analysis showed that the DOX-loaded polymer nanoscaffolds internalized the drugs 8-10× higher compared to free DOX. Both the synthesis of new classes of poly(ester-urethane)s via melt polycondensation approach and the enzyme-responsive drug delivery concept were accomplished for the first time. Thus, the present investigation is expected to open up new opportunities for l-tyrosine polymeric materials in biomaterial and thermoplastic applications.

EDC/DMAP-mediated direct condensation of dicarboxylic acids and diols: A concise synthesis of extra large polyether macrocyclic lactones and their X-ray structures

We report the EDC/DMAP-mediated direct condensation reactions of dicarboxylic acids with diols and synthesis of new classes of 18-48-membered, small and extra-large polyether macrocyclic lactones. The methodology was executed by using various dicarboxylic acids linked via aliphatic, polyether and aromatic linkers and different diols (e.g., (Z)-but-2-ene-1,4-diol, but-2-yne-1,4-diol, 2,2′-thiobis(ethan-1-ol), 2,2′-(benzylazanediyl)bis(ethan-1-ol), 2,2′-oxybis(ethan-1-ol)). The condensation reactions of dicarboxylic acids with diols afforded 1:1 (18-24-membered) and 2:2 (36–48-membered) polyether macrocyclic lactones. The synthesis of small and extra-large polyether macrocyclic lactones was accomplished without using a template and relatively simple reaction conditions. All the reported macrocyclic lactones were separated by column chromatography and characterized by 1H, 13C NMR and HRMS analyses. The solid state (X-ray) structures of representative polyether macrocyclic lactones were also reported.

Bis(N-amidinohydrazones) and N-(amidino)-N′-aryl-bishydrazones: New classes of antibacterial/antifungal agents

The emergence of multidrug-resistant bacterial and fungal strains poses a threat to human health that requires the design and synthesis of new classes of antimicrobial agents. We evaluated bis(N-amidinohydrazones) and N-(amidino)-N′-aryl-bishydrazones for their antibacterial and antifungal activities against panels of Gram-positive/Gram-negative bacteria as well as fungi. We investigated their potential to develop resistance against both bacteria and fungi by a multi-step resistance-selection method, explored their potential to induce the production of reactive oxygen species, and assessed their toxicity. In summary, we found that these compounds exhibited broad-spectrum antibacterial and antifungal activities against most of the tested strains with minimum inhibitory concentration (MIC) values ranging from <0.5 to >500μM against bacteria and 1.0 to >31.3μg/mL against fungi; and in most cases, they exhibited either superior or similar antimicrobial activity compared to those of the standard drugs used in the clinic. We also observed minimal emergence of drug resistance to these newly synthesized compounds by bacteria and fungi even after 15 passages, and we found weak to moderate inhibition of the human Ether-à-go-go-related gene (hERG) channel with acceptable IC50 values ranging from 1.12 to 3.29μM. Overall, these studies show that bis(N-amidinohydrazones) and N-(amidino)-N′-aryl-bishydrazones are potentially promising scaffolds for the discovery of novel antibacterial and antifungal agents.

Exploitation of Intramolecular Glaser–Eglinton–Hay Macrocyclization for the Synthesis of New Classes of Optically Active Aza-Oxo-Thia Polyether Macrocycles from Amino Alcohol Building Blocks

We report an intramolecular Glaser–Eglinton–Hay coupling as an unprecedented route for assembling optically active aza-oxo polyether macrocycles containing a 1,3-diyne unit from enantiopure amino alcohol building blocks and suitable linkers. Furthermore, the conversion of the 1,3-diyne unit of the aza-oxo polyether macrocycles into a thiophene ring led to the assembly of new classes of optically active aza-oxa-thia (heterotopic) polyether macrocycle analogues of classical 18-C-6 and 18-C-5 systems.

Possible increase in the critical temperature of high-temperature superconductors based on the synthesis of new classes of HTSC compounds

The effect of exchange enhancement of electron-phonon interactions in high-temperature superconductor (HTSC) systems is examined and an upper bound is determined for applicability of the quasilinear equations. The spin-phonon interaction in the HTSC phase is described. It is found that if the resonance wave vector krez ≪ pF, then use of the quasilinear equations is justified, since krez is on the order of the inverse correlation length kc which, in turn, does not exceed the inverse coherence length (i.e., kc ≪ pF). Thus, the quasilinear calculation of Tc is correct when the spin-phonon coupling parameter ξ ≫ 1 and can be used to determine the synthesis characteristics for new HTSC materials with higher Tc.

ChemInform Abstract: Chemical Biology Protein Modification in a Trice

AbstractReview: 10 refs.

Chemical biology: Protein modification in a trice.

Organometallic reagents have been developed that chemically modify proteins and peptides specifically at cysteine amino-acid residues — potentially offering a general route to making therapeutically useful compounds. See Letter p.687 These authors demonstrate that palladium(II) complexes can be used in efficient and highly selective cysteine conjugation reactions that are rapid and robust, and the resulting aryl bioconjugates are stable towards acids, bases, oxidants and external thiol nucleophiles. The broad utility of the new bioconjugation platform was further corroborated by the synthesis of new classes of stapled peptides and antibody–drug conjugates. Previously the use of transition-metal based reactions to modify complex biomolecules has proved problematic due mainly to the need for stringent reaction conditions and the presence of multiple reactive functional groups in peptides.